Very few synthetic routes exist in the public domain relative to methods of making mercaptoalkylalkyldialkoxysilanes. U.S. Pat. No. 4,082,790 (Apr. 4, 1978), for example, assigned to the same assignee as the present invention, describes a process for making mercaptans similar to the compositions prepared herein, by reacting a haloalkoxysilane with a mixture containing hydrogen sulfide and either ammonia or a hydrocarbon amine such as butyl amine. However, this process suffers from the disadvantage that it requires ventilation equipment, a pressure reactor, and filtration of by-products such as ammonium chloride in an anhydrous and oxygen free atmosphere.
However, nothing in the public domain describes a method of making mercaptoalkylalkyldialkoxysilanes by reacting an alkoxysilane containing unsaturated organic groups with a sulfur containing organic acid in the presence of a peroxide catalyst, followed by methanolysis in the presence of a basic catalyst to obtain the mercaptoalkylalkyldialkoxysilane.